The present invention relates to a recording medium, a recording-medium management method and a recording-medium management system, and more particularly, it relates to a recording medium for managing decryption of contents which are stored in the recording medium, propriety of access, etc., to the recording-medium management method of performing authentication about this recording medium, and to the recording-medium management system that performs authentication etc. about the recording medium.
The technology of copy protection for protecting copyrights of a music software, video software, and application software, is becoming important with the spread of digitized data.
Particularly, a DVD (Digital Versatile Disc) video disc or a DVD-ROM disc etc. which adopts the digital recording system can be accompanied as representative examples of the software for which a copy protection is required. Encryption technology has been conventionally used for the copy protection to the video software of these digital recordings.
The copy protection method using encryption technology performs effectively about the DVD video disc or DVD-ROM disc with which the already encrypted data is recorded. However, in the case of DVD-RAM with which a user can record a new data, the following problems will arise.
(1) Management of the “encryption key” needed when encrypting is difficult.
(2) Since a powerful encryption is difficult for the data recording reproducing equipment (for example, DVD-RAM recorder which can perform recording and playback in digital like the analog video cartridge recorder which has spread widely) which is provided over a user's hand, a code is easy to be broken.
(3) In the case of a data recording reproducing equipment which can perform encryption and its decryption within the equipment, if the data is again encrypted with the original data recording playback equipment after decrypting the data which the user once created and encrypted with another data recording playback equipment, the contents of data to be protected against a copy can be copied easily.
Because of these problems, it is difficult to operate the copy protection using the conventional encryption technology effectively about the record playback equipment of digital video data.
Moreover, if an original copy protection processing is performed for a data recording medium for DVD-RAM by the DVD-RAM drive system, there will be a problem that a copy protection processing circuit becomes complicated when reproducing the medium with a DVD-ROM drive or reproducing a DVD-ROM disc with the DVD-RAM drive
This also becomes the factor which increases the product cost of the DVD-RAM drive.